Hydraulic by-pass system and valve therefor



March 25, 1952 J, 5, 2,590,454

HYDRAULIC BY-PASS SYSTEM AND VALVE THEREFOR Filed Sept. 13, 1949 2Sl-lEETS-SHEET l INVENTOR. J0 H N S.'P I LCH March 25, 1952 J. s. 'PILCH2,590,454

HYDRAULIC BY-PASS SYSTEM AND VALVE THEREFOR Filed Sept. 15, 1949 2SHEETS--SHEET 2 iNVENTOR;

Patented Mar. 25, 1952 HYDRAULIC BY-PASS SYSTEM AND VALVE THEREFOR JohnS. Pilch, Ware, Mass.

Application September 13, 1949, Serial No. 115,331

6 Claims.

This invention relates to hydraulic systems and a new and improved valvetherefor.

An object of the invention is to provide a hydraulic system particularlyadapted for use in such devices as hydraulically operated loadingbuckets carried by tractors or other vehicles and to a new and improvedhydraulically operated bucket and flow control valve for such systemswhich increases the speed of tripping of the bucket and also lowering orreturn of the bucket for loading, and, therefore, considerablyincreasing the speed of loading with the device.

Another object of the invention is to provide a hydraulic system andflow control valve therefor which bypasses the hydraulic fluid thusshortening the path of travel of the hydraulic fluid under certainconditions and, therefore, tending to keep such fluid cool and eliminatevacuum created in the system and speeds up the operation of dumping thebucket.

Another object of the invention is to provide a hydraulic system andflow control valve therefor of the type set forth which valve operatesautomatically during the lowering or return of the bucket and which isrelatively simple in construction yet efiicient in operation.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanyingdrawings. I, therefore, do not wish to be limited to the details ofconstruction and arrangement of parts shown and described, as thepreferred form has been shown by way of illustration only.

Referring to the drawings:

Fig. 1 is a side View of a tractor carried, hydraulically operatedloading bucket embodying the invention;

Fig. 2 is a sectional view of a flow control valve constructed accordingto the invention, showing the valve in neutral position; and

Fig. 3 is a View similar to Fig. 2, but showing the valve in operativeposition during the return or lowering of the bucket.

While the hydraulic system and flow control valve have been shown asapplied to a hydraulically operated loading bucket, this has been doneis carried by a tractor ll) of conventional construction.

On the tractor I0 is provided the reservoir tank I I for the hydraulicfluid for the hydraulic system and the hydraulic pump l2 of conventionaltype which is mechanically connected to and driven by the engine of thetractor I ll in the usual manner.

comprises a pair of push arms [3, one on each side of the tractor I0,only one of which push arms.

is shown. These push arms I3 carry the loading bucket I4 which isactuated by a pair of rams 15, one on each side of the tractor l0, andof which only one is shown, and the rams each have piston portionspositioned within cylinders l6 and adapted to be actuated therein byhydraulic force to thereby actuate the rams l 5 in the usual manner andsaid rams l5 are connected at their opposite ends to the supports 65.

The hydraulic pump I2 is adapted to supply fluid through pipe line I! tothe usual four-way hydraulic control valve I8 which is provided with theoperating or control lever 19. The return pipe line 20 is provided fromsaid valve I8. and has a branch 2| for returning fluid to the reservoiror tank II and a branch 22 for returning fluid directly to pump l2.

Control lever I Be is provided for dumping bucket M as hereinafterdescribed.

Control valve I8 is connected by pipe lines 24 and 25, and 56 and 51 toeach of the flow control valves 26, one of which is provided for thecylinders l6 and is connected by the two sets of pipe lines 21 and 28;and 29 and 30 to each of the cylinders l6 with each of said pipe lines21 and 29 connected to each of said cylinders l6 adjacent. correspondingends and said pipe lines 28 and 30 also connected to each of saidcylinders adjacent the corresponding ends opposite those at which thelines 21 and 29 are connected so that both of the rams l 5 function in asimilar directionsimultaneously.

The second flow control valve is provided for bypassing the hydraulicfluid and thus speeding up the operation of tipping or dumping thebucket as well as keeping the fluid cool and eliminate vacuums beingcreated in the system. This second flow control valve 26 is connected tocontrol valve I8 by lines 56 and 51.

The hydraulic bucket control system also includes a pair of cylinders62, one on each side of the tractor l0, only one of which cylinders isshown. These cylinders 62 each are pivotally mounted at theirconnections 68a with the sup- The loading arrangement, as shown in Fig.1,

porting frame, and each is adapted to receive a ram 63, which rams 63are pivoted at their outer ends 68 to a link 64 which links arepivotally connected at 61 to the bucket l4.

Each set of push arms |3 and links 64 are connected by links 66 whichare pivoted at their ends 66a and 66b to the links 64 and push arms |3respectively.

The cylinders 52 are each connected adjacent their opposite ends by setsof pipe lines 60 and BI, and 58 and 59 to the flow control valve 26therefor and control valve I8 is provided with a control or operatinglever |9a for controlling the by draulic system for controlling thetipping or rotation of bucket I4.

Each of the flow control valves 26 comprises a valve body 25a which isprovided with a longi tudinal opening and slideway 3| extendingtherethrough and closed at its opposite ends by threaded caps 32 and 33.

Communicating with said longitudinal opening are oppositely disposedsets of openings 34 and 35, and 36 and 31 adapted to communicate withpipe lines 24, 25, 21, 28, 29 and 3|) through respective fittings 38,39, 49 and 4| which connect said pipe lines to said valve body 26a.

Mounted for sliding movement on said slideway 3| is slide 42 which hasthe transverse passage or slot 43 adapted to align an oppositelydisposed set of openings 34 and 35 for the passage of fluid throughsaid'slide 42.

Theslide 42 has spring retainers 44 and 45 at its opposite ends adaptedto engage the adjacent ends of coil centering springs 46 and 41respectively which have their opposite ends engaging threaded caps 32and 33 and said springs, in the absence of hydraulic force serve toretain the slide in neutral position as shown in Fig. 2.

Spring retainer 45 has an opening 48 there through communicating withcheck valve chamber 41%!into which said retainer 45 is threaded and insaid chamber 49 is check valve coil spring 55 which is a relativelylight coil spring for retaining check Tvalve normally inclosed positionover opening 52 which communicates'with passage or slot 43.-

The openings 34 and 36 are each connected by bypass openings 53 and 54respectivelyto the opposite ends of slideway 3| Wherebypressure througheither of said lines 24 or 25 will cause pressure through the respectivebypass 53 or'54 and thereby cause "movement of slide 42 in'slideway 3|.

When the fluid is returning from the lower portion of cylinders I6through lines 38 and 32, that is, when the bucket 4 is being lowered forloading, considerable time elapses for .the passage of the fluidthrough'flow control valve 26 to control valve l8 and thenthrough thepressure line to lines 21 .and 29 which takes considerable time andcorrespondingly slows up the loading operation.

In Fig. 2, the slide 42 is shown in neutralrposition in slideway 3|, inwhich position it is snor- Irrally retained by springs 46 and 47 andin'Fig. 3. slide 42 is shown in operative pos'ition'.for bypassing fluidto speed the lowering or return of the bucket to increase the speed ofoperation.

When fluid is being forced into the cylinder 29 -to raise the bucket,fluid first passes through bypass opening 53to augment the force ofspring 46 against slide 42 and move slide 42 in slideway 3| to suchposition as to establish communicae tion between lines 24 and 28 which.continues' as long as hydraulic pressure is applied through 4 line 24.However, when pressure is shut off through line 24 by valve l8, slide 42returns to neutral position to prevent passage of fluid in eitherdirection and thus hold the bucket in adjusted position.

When the bucket is to be lowered, valve H3 is so adjusted as to applypressure through line 25 which through bypass 54 applies pressureagainst the corresponding end of slide 42, thus augmenting the pressureof spring 41 to effect movement of slide 42 to the position shown inFig. 3 which establishes communication between openings 34 and 35through passage 43 and also establishes communication between openings36 and 31 and lines 25 and 21 and fluid pressure in passage 43 againstcheck valve 5| opens said valve, as shown in Fig. 3 and allows thedirect passage of fluid from line 28 through passage 43 and passage 52and check valve 5| to opening 37 and line 2'l without passing throughcontrol valve |8 as would otherwise be required.

This bypassing of the fluid path increases .considerably the speed ofoperation of the device.

I have found that by providing passage 52 and check valve 5|, thatsuction or vacuum in the lines to the upper end of cylinder |6 plus oilpressure behind check valve 5| will open said check valve 5| during thelowering of the bucket M for loading or tipping of the bucket forunloading and allow hydraulic fluid to pass directly from the returnline to the pressure line in flow control valve 23 without the necessityof returning through control valve 18 and then passing from said valvethrough the lines to the cylinders. This considerably speeds up the timerequired for the passage of the fluid from the lower end of thecylindersto the upper end thereof and correspondingly .increases thespeed of lowering the arms and the bucket M and thereby speeds up theloading operation and also increases the speed of tipping of the bucketand, therefore, the unloading operation.

From the foregoing it willbe seen that I have provided simple, efficientand economical means for obtaining all of the objects and advantages ofthe invention.

Having described my invention, I claim:

1. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to bepositioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to be moved by fluidpressureto a position wherein it permits flow from said return line into saidfirst passage in said slide, a second fluid passage in said slide andcommunicating with said first fluid passage and adapted to establishfluid passage through said slide from said first fluidpassage to thepressure line-and valve means in said slide for controlling 'the passageof fluid through said second passage and allow fiuid to pass directlyfrom said return line to said pressure line without passing through thecontrol valve for said hydraulic system.

2. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to beposii tioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to be movedby fluid pressureto a position wherein it permits flow from said return line into saidfirst passage in said slide, a second fluid passage in said slide andcommunicating with said first fluid passage and adapted to establishfluid passage through said slide from said first fluid passage to thepressure line, and a check valve in said second fluid passage in saidslide for controlling the passage of fluid through said second passageand allow fluid to pass directly from said return line to said pressureline without passing through the control valve for said hydraulicsystem.

3. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to bepositioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to be moved by fluid pressureto a position wherein it permits flow from said return line into saidfirst passage in said slide, a second fluid passage in said slide andcommunicating with said first fluid passage and adapted to establishfluid passage through said slide from said first fluidpassage to thepressure line, and valve means in said slide for controlling the passageof fluid through said second passage and allow fluid to pass directlyfrom said return line to said pressure line without passing through thecontrol valve for said hydraulic system and means for normally retainingsaid slide in neutral position in said body.

4. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to bepositioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to be moved by fluid pressureto a position wherein it permits flow from said return line into saidfirst passage in said slide, a second fluid passage in said slide andcommunicating with said first fluid passage and adapted to establishfluid passage through said slide from said first fluid passage to thepressure line, and a check valve in said second fluid passage in saidslide for controlling the passage of fluid through said second passageand allow fluid to pass directly from said return line to said pressureline without passing through the control valve for said hydraulicsystem, and means for normally retaining said slide in neutral positionin said body.

' 5. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to bepositioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to r be moved by fluidpressure to a position wherein it permits flow from said return lineinto said first passage in said slide, a second fluid passage in saidslide and communicating with said first fluid passage and adapted toestablish fluid passage through said slide from said first fluid passageto the pressure line, and valve means in said slide for controlling thepassage of fluid through said second passage and allow fluid to passdirectly from said return line to said pressure line without passingthrough the control valve for said hydraulic system and spring membersin said valve body adjacent the opposite sides of said slideway fornormally retaining said slide in desired position in said valve body.

6. In a flow control valve adapted to be interposed in the lines of ahydraulic system having a pressure line and a return line and to bepositioned between a hydraulic cylinder and the control valve thereforto increase the speed of operation of the hydraulic system, a valve bodycommunicating with said lines, a slideway in said body adapted tocontrol the passage of fluid through said body, a pressure operatedslide in said slideway, said slide having a first fluid passagetherethrough and said slide being adapted to be moved by fluid pressureto a position wherein it permits flow from said return line into saidfirst passage in said slide, a second fluid passage in said slide andcommunicating with said first fluid passage andadapted to establishfluid passage through said slide from said first fluid passage to thepressure line, and a check valve in said second fluid passage in saidslide for controlling the passage of fluid through said second passageand allow fluid to pass directly from said returnline to said pressureline without passing through the control valve for said hydraulicsystem, and spring members in said valve body adjacent the oppositesides of said slideway for normally retaining said slide in desiredposition in said valve body.

JOHN S. PILCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,198,216 Hanson Sept. 12, 19161,989,387 Vickers Jan. 29, 1935 2,193,736 Onions Mar, 12, 1940 2,200,578Mahon i. May 14, 1940 2,267,284 Livers Dec. 23, 1941 2,367,682 KehleJan. 23, 1945 2,451,101 Leschinsky Oct. 12, 1948 2,453,755 Perman Nov.16, 1948 2,470,471 Carleton May 17, 1949

